Two-temperature thermostat



Oct. 13, 1936; F. w. POWERS TWO-TEMPERATURE THERMOSTAT Filed Sept. 4,1934 Patented Oct. 13, 1936 UNITED STATES PATENT OFFICE TWO-TEMPERATURETHERMOSTAT Fred'W. Powers, Chicago, Ill., asslgnor to The PowersRegulator Company, Chicago, Ill.

My invention relates to thermostats, and particularly to a thermostat ofthe type known as a two-temperature thermostat; that is, an instrumentadapted to control temperature in two rather widely different ranges.

It has been found to be desirable for the heat regulation of offices,school rooms, etc., from a remote point, to provide for normalthermostatic control of the heat according to the setting of thethermostats in the individual spaces, and, by the use of collateraldevices, manually operable at a central point, to effect adjustment ofthe individual thermostats so asto provide for regulation at a muchlower temperature. Thus, for operation during working hours, theindividual thermostats may be set to maintain a temperature of 70, andthe control device, operable from the central point, may be arranged tochange the adjustment of all thermostats to provide for the maintenanceof a temperature during non-working hours of This result has beenaccomplished in several different manners, and in general, the operationof such devices has been satisfactory.

In all apparatus of character described, means should be provided,associated with the individual thermostats, for segregating theindividual thermostats from the common low-temperature controllingmeans, in order that the occupant of any space may, by a simpleadjustment, prevent the action that would result in a lowering of thetemperature. This likewise, is common to many of the instruments now inuse. However, in the device herein disclosed I provide not only for thedesired functions, but in addition, I provide for a return to normaloperating conditions. of the in strum ent following a reversal of thetemperature reducing action, without any necessary attention from theoccupant. In other words, all that the occupant needs to do is to setthe instrument for normal operation; then at the next actuation from thecentral point the instrument will be restored to its normal operatingcondition.

The invention will be more readily understood by reference to theaccompanying drawing, in which;

Fig. 1 is a longitudinal, vertical, sectional view through an instrumentconstructed in accordance with my invention;

Fig. 2 is a sectional view on the line 2-2 of Fig. 1; and

Fig. 3 is a face view of the instrument with the cover removed. I

In the drawing I'have illustrated the instrument as including a baseplate ill to which the various parts are secured. The instrument isenclosed by a cover ll, having a bulb thermometer l2 thereon, andopenings through which adjusting keys may be inserted. 5 The main partof the instrument consists of a casting l3, having air passages l4-I5therein-that communicate with air pipes l6-l| respectively, the pipe Itbeing connected to a source of air under pressure, and the pipe l1 10being connected to an air-operated heat control valve. The pipe l8,which is connected to the passage i9, is independently connected to asource of fluid under pressure, a hand valve therein (not shown) beingactuated to admit 15- air into the passage I9 for operating theadjustment-changing mechanism that constitutes one of the novel featuresof the instrument.

Mounted over the recess 20 in the casting I3 is a diaphragm 2i, and adouble valve 22-23 20 controls the escape of air from the passage ll tothe passage l5. A spring 24 tends to unseat the valve 22, while a spring25 tends to seat the valve 23. A fiat spring 26 overlies the valve bodythat is connected to the diaphragm 2|, and 25 directly overlying thespring 26 and the end of the valve body is a bridge member 21 thatsupports a pair of bellows 28-29. Each of the bellows contains avolatile substance selected to function within the desired temperaturerange. 30 Two bellows for operation in unison are used rather than onebellows 01 large size. I have found that accurate operation is securedwith the arrangement shown, and considerable space is saved, as a resultof such use. The outer faces 35 of the bellows are supported against anarm 30 secured at its upper end to the face of the main casting, and atits lower end having screw thread engagement with a threaded pin 3|. Thepin carries a small gear 32' that meshes with an in- 40 dicating dial33, a key being used to engage the squared outer end of the pin in orderto rotate the same for adjustment purposes.

Mounted over a recess in the arm 30 is a small diaphragm 34, therebyproviding a cham- 5 her 35 to which air is admitted through the passage36. A stem 31 projects inwardly from the face of the diaphragm 34,through an opening, and into contact with the bridge member 38 on theouter face of the bellows, and it will be 50 seen that as air underpressure is admitted into the chamber 35, a thrust will be exertedagainst the bellows that will serve, in effect, to change the adjustmentof the arm 30, by separating the bridge 38 and the arm 30.

Air is admitted to the chamber 35 through the passage 36, the passageI9, and the air pipe l8 around the restriction screw 39a. This air iscontrolled by a valve 39 operated to closed and exhaust positions bymeans of the threaded member 40. A spring 4| thereon tends to rotate thethreaded member to a position in which the valve 39 will close theexhaust passage and admit air to the passage 36, through the branch 42.When, however, the threaded member 40' is rotated by means of a keyengaging the outer end thereof, air will be exhausted and prevented fromentering the passage 42.

A second branch passage 43, open to the pipe I8, is connected to asmallbellows 44 mounted on the arm 30, and adapted to expand outwardlyand operate an arm 45. This arm underlies a section of a disk 46 fixedto the threaded member 40, arecess and projection 41 on the arm and diskconstituting means for temporary engagement in order to hold thethreaded member in open position whenever the bellows 44 is distended.Preferably the disk will be given a distinctive color, and will bevisible through an opening in the cover.

The operation is as follows:

Assume a supply of air under pressure in the supply pipe l6 and asetting of the instrument by means of the pin 3| for a desiredtemperature, an increase over that temperature will result in a thermalexpansionof the bellows 2829. This will cause an inward movement of thediaphragm 2 I, the-overcoming of the spring 24, and the seating of thevalve 22. Further inward movement will result in unseating the valve 23,and the admission of air through the passage l4 into the space 20, andto the passage l5 leading to the air controlled heat valve, thus closingit. Upon a reversal of movement of the bellows due to a cooling of thespace, a reverse action will take place; that is, the valve 23 willfirst be closed,

,and then as the movement continues, the valve 22 will be opened,permitting air to exhaust and the heat valve to open.

When, at the close of the day, the engineer wishes to reduce thetemperature of all the spaces to which heat is supplied, he opens avalve and admits air to the pipe I8. The air so admitted enters thebranch 43 and distends the bellows 44 and swings outward the arm 45 intocontact with the disk 46. Air also enters the branch 42 and the passage36 into the space 35 causing the diaphragm 34 to be moved and to exertpressure through the stem 31, against the wall 38 that overlies thebellows za -za. This results in the equivalent of an expansion of thesaid bellows, and an interruption of the supply ofheat. Consequently,while the pressure is exerted as described, a much lower temperaturewill prevail in the space under regulation.

In the event that an occupant wishes to use a particular space and tohave heat therein, he applies a key to the threaded member 40, turns itand the disk .46 against the tension of the spring 4|, thus opening thevalve 39 and permitting air to exhaust from the space 35 more rapidlythan it can enter through the restriction screw 39a. This does not,however, stop the supply to the branch 43, and to bellows 44 which isunaffected by the movement of the valve 39. Consequently, the threadedmember is retained in its position due to the engagement of the recessvand projection 41 on-the disk and the arm 45 and normal operation of thebellows 38-39 is restored. In the morning, when the engineer wishes torestore normal heat conditions, the supply of air in the pipe I8 isdiscontinued, the bellows 44 will resume its normal position and thethreaded member will be returned under the influence of the spring 4|,thus resetting the parts without any action by the occupant.

It is obvious that many of the elements shown and described may bemodified and I do not wish to be limited except as indicated in theappended claims.

I claim:

1. In a device of the class described, the combination of valve meansfor controlling the passage of air to a heat regulating valve, athermosensitive element for actuating said valve means, means operableby air under pressure from an independent supply for changing the valveoperating function of said thermosensitive element, manually operablemeans for interrupting the supply of air to said means for changing thefunction of said thermosensitive element, and means operable by saidindependent supply of air for retaining said manually operable means ininterrupting position only during the period when air is being suppliedfrom independent source.

2. In a device of the class described, the combination of valve meansfor controlling the passage of air to a heat regulating valve,thermosensitive element for actuating said valve means, means erablemeans in interrupting position only during the period when air is beingsupplied from said independent source.

3. In a thermostat of the leak type, the combination of means providinga movable wall adapted, when under pressure, to affect a. change ofadjustment of the thermostat, an independent conduit for supplying fluidunder pressure to said movable wall, a manually operable valve on saidthermostat adapted to be positioned to prevent actuation of said wall bythe fluid under pressure,

a second movable wall carrying a detent, and

means on said valve adapted to be engaged by said detent to hold thesame at adjusted position so long as fluid under pressure is beingsupplied to said last named movable wall.

4. In a thermostatic instrument, the combination of a basecontaining airpassages, a valve in said base for controlling the delivery of air to aheat valve through said passages, a thermally expansible element mountedabove said base and adapted to control the said air valve, an armconnected at its two ends to said base, one end being adjustable, saidarm acting as a backing for the thermally expansible element, said armand actress combination of a base containing an air passage, a valve insaid passage for controlling the delivery of air to a heat valve throughsaid passage, a thermostatic element mounted above said base and adaptedto control the said air valve, an arm connected at its two ends to saidbase, one end providing an adjustable connection, said arm acting as anouter support for the thermostatic element, said arm and base having anair passage connected to a supply of air independent of said firstmentioned air supply, a fluid expansible member carried by the arm andopen to said last named air passage and adapted to act on saidthermostatic element to change its adjustment, and manually operablemeans, also carried by said arm, and adapted to interrupt the supply ofair to said fluid expansible member.

6. In a two-temperature range thermostat, the combination of a basecontaining an air passage, a valve in said passage for controlling thedelivery of air to a heat valve through said passage, 8. thermostaticelement mounted above said base and adapted'to control the said airvalve, an arm connected at its two ends to said base, one end providingan adjustable connection, said arm acting as an outer support for thethermostatic element, said armand base having an air passage connectedto a supply of air independent of said first mentioned air supply, afluid expansible member carried by the arm and open to said last namedair passage and adapted to act on said thermostatic element to changeits adjustment, and manually operable means, also carried by said arm,and adapted to interrupt the supply of air to said fluid expansiblemember, and means operated by said last named supp of air for retainingsaid manual means in interrupting position only during the maintenanceof said supply of air.

'7. In combination, a base having air "passages, a valve for controllingsaid passages, a thermostatic element for actuating said valve, a fluidexpansible element adapted to act on said thermostatic element to changethe adjustment thereof, said fluid expansible member being adapted foroperation by an independent supply of air, manually operable means fornullifying a change of adjustment of said thermostatic element, and asecond fluid expansible member connected to last named supply of air,for retaining said manual means in nullifying position only during thecontinuance of said supply of air.

8. In combination, a base having an air passage from a source of supplyto a heat valve, a valve for controlling said passage, a thermostat foractuating said valve, a support for said thermostat mounted on, andadjustable relative to said base, a diaphragm carried by said member andadapted to exert a pressure tending to change the adjustment of saidthermostat, said member having a passage for air from an independentsource to said diaphragm, manually operable means on said member forinterrupting the supply ol! air to said diaphragm, and means independentof said diaphragm and operated by the same supply of air for-retainingsaid manual means in interrupting position.

9. In combination, a base having an air passage from a source of supplyto a heat valve, a valve forcontrolling said passage, a thermostat foractuating said valve, a support for said thermostat mounted on, andadjustable relative to, said base, a diaphragm carried by said memberand adapted to exert a pressure tending to change the adjustment of saidthermostat, said member having a passage for air from an independentsource to said diaphragm, manually op.- erable means on said member forinterrupting the supply of air to said diaphragm, and a fluid expansiblemember independent of said diaphragm, and mounted on said member andconnected to said last named supply of air for retaining said manualmeans in interrrupting position.

i FRED W. POWERS.

